diff --git a/scenarionet/examples/combine_dataset_and_run.py b/scenarionet/examples/combine_dataset_and_run.py
index 61c69e8..bf8beb9 100644
--- a/scenarionet/examples/combine_dataset_and_run.py
+++ b/scenarionet/examples/combine_dataset_and_run.py
@@ -38,22 +38,23 @@ if __name__ == '__main__':
         }
     )
     success = []
-    env.reset(force_seed=2)
     while True:
-        env.reset(force_seed=2)
-        for t in range(10000):
-            o, r, d, info = env.step([0, 0])
-            assert env.observation_space.contains(o)
-            c_lane = env.vehicle.lane
-            long, lat, = c_lane.local_coordinates(env.vehicle.position)
-            # if env.config["use_render"]:
-            env.render(
-                text={
-                    "seed": env.engine.global_seed + env.config["start_scenario_index"],
-                }
-            )
+        for seed in [91]:
+            env.reset(force_seed=seed)
+            for t in range(10000):
+                o, r, d, info = env.step([0, 0])
+                assert env.observation_space.contains(o)
+                c_lane = env.vehicle.lane
+                long, lat, = c_lane.local_coordinates(env.vehicle.position)
+                # if env.config["use_render"]:
+                env.render(
+                    text={
+                        "seed": env.engine.global_seed + env.config["start_scenario_index"],
+                    }
+                )
 
-            if d:
-                if info["arrive_dest"]:
-                    print("seed:{}, success".format(env.engine.global_random_seed))
-                break
+                if d:
+                    if info["arrive_dest"]:
+                        print("seed:{}, success".format(env.engine.global_random_seed))
+                        print(t)
+                    break
diff --git a/scenarionet/tests/local_test/_test_combine_dataset_local.py b/scenarionet/tests/local_test/_test_combine_dataset_local.py
index 9b5621f..000953e 100644
--- a/scenarionet/tests/local_test/_test_combine_dataset_local.py
+++ b/scenarionet/tests/local_test/_test_combine_dataset_local.py
@@ -14,7 +14,7 @@ def _test_combine_dataset():
     combine_path = os.path.join(SCENARIONET_DATASET_PATH, "combined_dataset")
     combine_multiple_dataset(combine_path, *dataset_paths, force_overwrite=True, try_generate_missing_file=True)
     os.makedirs("verify_results", exist_ok=True)
-    success, result = verify_loading_into_metadrive(combine_path, "verify_results", steps_to_run=250)
+    success, result = verify_loading_into_metadrive(combine_path, "verify_results")
     assert success
 
 
diff --git a/scenarionet/tests/test_combine_dataset.py b/scenarionet/tests/test_combine_dataset.py
index ffabed4..8f24603 100644
--- a/scenarionet/tests/test_combine_dataset.py
+++ b/scenarionet/tests/test_combine_dataset.py
@@ -21,9 +21,11 @@ def test_combine_multiple_dataset():
         summary, sorted_scenarios, mapping = read_dataset_summary(dataset_path)
         for scenario_file in sorted_scenarios:
             read_scenario(os.path.join(dataset_path, mapping[scenario_file], scenario_file))
+        num_worker = 4 if len(summary) > 4 else 1
         success, result = verify_loading_into_metadrive(dataset_path,
                                                         result_save_dir="test_dataset",
-                                                        steps_to_run=300)
+                                                        steps_to_run=1000,
+                                                        num_workers=num_worker)
         assert success
 
 
diff --git a/scenarionet/verifier/utils.py b/scenarionet/verifier/utils.py
index 9aa4d9a..4e63f0b 100644
--- a/scenarionet/verifier/utils.py
+++ b/scenarionet/verifier/utils.py
@@ -11,7 +11,7 @@ from metadrive.scenario.utils import get_number_of_scenarios
 from functools import partial
 
 
-def verify_loading_into_metadrive(dataset_path, result_save_dir, steps_to_run=300, num_workers=8):
+def verify_loading_into_metadrive(dataset_path, result_save_dir, steps_to_run=1000, num_workers=8):
     if result_save_dir is not None:
         assert os.path.exists(result_save_dir) and os.path.isdir(
             result_save_dir), "Argument result_save_dir must be an existing dir"
@@ -45,7 +45,7 @@ def verify_loading_into_metadrive(dataset_path, result_save_dir, steps_to_run=30
     if result:
         print("All scenarios can be loaded successfully!")
     else:
-        print("Fail to load all scenarios, see log for more details! Number of failed scenarios: {}".format(logs))
+        print("Fail to load all scenarios, see log for more details! Number of failed scenarios: {}".format(len(logs)))
     return result, logs